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Mosquito News 



Vol. 31, No. 1 



OPERATIONAL AND SCIENTIFIC NOTES 



Mosquitoes Feeding on Engorged Mosquitoes 1 

A. Burns Weathersby, Hyong-Sun Ah 2 and 

John W. McCall 

Department of Entomology, University o£ Georgia, 

Athens, Georgia 30601 

Harris, et al. (1969) reported that adult female 
Aedes aegypti would feed on lepidopterous larvae 
Cdero euphorbia and speculated on the possibility 
that haemolymph of the newly discovered host 
could be adequate for the mosquito to produce 
viable eggs. He also considered the potential of 
insect pathogens being transmitted by these mos- 
quitoes. 

We have always considered that female mos- 
quitoes obtained blood meals from vertebrate hosts 
and male mosquitoes fed on plant secretions. Of 
course we knew that both would take liquids such 
as sugar water, juices from raisins, oranges, apples 
or other fruit, but their potential for feeding on 



One of our technicians, at the beginning of her 
work with us, reported that she thought she had 
seen one mosquito taking blood from another en- 
gorged one. Following Harris' report, experi- 
ments were designed to test her observation and to 
determine the prevalence of this behavior. 

Materials and Methods. Female pupae of 
Aedes aegypti and Culex pipicns were allowed to 
emerge in 5-inch cylindrical plastic cages 6 inches 
high. When the adults were 4-6 days old thty 
were allowed to engorge with blood from a 
chicken. Immediately following engorgement of 
these mosquitoes, 15-20 starved female A. aegypti 
between 4-6 days old were introduced into the 
cages and observed. Small glass observation cham- 
bers were fabricated from No. 1 coverslips in 
which one or two engorged females were im- 
mobilized on a glass rod. Several starved A. 
aegypti were confined with them and photographic 
records of feeding were made from these cham- 
bers. 



- -" v*vKr. . c - ~^t~z 



Fig. 1.- 



-Aedes aegypti feeding on an engorged Aedes aegypti. 



members of the same family or other arthropods 
had been overlooked. 



x This investigation was supported in part by 
Public Health Service Research Grant AI 05253, 
from the National Institute of Allergy and In- 
fectious Diseases. 

2 University of Georgia, Veterinary Diagnostic 
and Research Laboratory, Tifton, Georgia 31794. 



Results and Discussion. When starved female 
A. aegypti are introduced into cages of blood-en- 
gorged mosquitoes they are attracted to them and 
will attempt to feed. Some fly immediately to an 
engorged mosquito which may remain motionless 
while the hungry mosquito probes and begins to 
feed. (Fig. 1) 

A few engorged mosquitoes are disturbed and 
move away when another attempts to feed. Most 



March, 1971 



Mosquito News 



hi 



mosquitoes engorge rather rapidly while others, 
not so aggressive, delay probing and feeding. If 
feeding is not begun within 30 minutes from the 
time the "host" takes its blood meal the speed of 
feeding by the starved marauding mosquito is 
considerably slower than of those who feed im- 
mediately. A. aegypti will feed on A. aegypti as 
seen in Fig. 1, or on engorged C. pipiens. Some- 
times two or more mosquitoes may feed on one 
host. Most unfed mosquitoes were attracted to 
the engorged mosquitoes. 

Blood smears were prepared and stained from 
mosquitoes that robbed mosquitoes that had en- 
gorged on chicken blood infected with Plas- 
modium gallinaceum. As was anticipated, these 
mosquitoes also were infected with erythrocytic 
parasites and could be expected to develop an 
infection. Caged mosquitoes, especially from 
laboratory cultures, behave quite differently from 
wild mosquitoes but if this occurred in nature it 
would seem likely that a wider distribution of 
the malaria would be effected since it could be 
passed on to several mosquitoes. This might be 
especially true in the case where certain mosquitoes 
leave- the protected environment of a house or 
barn at dawn and fly into woodland or jungle 
environment. 

Acknowledgments. The authors are grateful 
to Jan Smith who drew our attention to the 
mosquitoes' behavior. 

References 

Harris, P., Riodan, D. F. and Cooke, D. 1969, 
Mosquitoes feeding on insect larvae. Science 

164:184-185. 



Collection Recokds. At Chappaqua, New 
York, four females were found in biting collec- 
tions on June 21, 1965. 

In Connecticut, specimens of A. thibaulti were 
found at four locations in the state, ranging 
from the southern area near New Haven 
(Bethany Bog) to a northern area at Simsbury 
which is located near the Connecticut-Massa- 
chusetts border. All specimens were adult females 
from biting collections as follows: two from Mt. 
Carmel on July 26, 1968; one from North Bran- 
ford on July 29, 1968; one from Simsbury on 
June 13, 1970; six from Bethany Bog, Bethany 
on June 30, 1970, and one additional specimen on 
July 8, 1970. 

Since A. thibaulti has not previously been re- 
ported from New York, the finding of this mos- 
quito at Chappaqua was of interest. However, it 
was of greater interest to have found it in Con- 
necticut — particularly since it occurred in four 
different places over a two-year period. This in- 
dicates that its presence was not due just to an 
isolated breeding focus located in the southern 
portion of the state. The significance of its pres- 
ence beyond the northern boundary of its pre- 
viously known range is not known. However, 
the collection sites in Connecticut are located 
beyond the extent of southern type woodlands, 
which indicates that the breeding habits of this 
species may not be as restricted as previously 
believed. 

Reference 

Carpenter, S. J. and La Casse, W. J. 1955. Mos- 
quitoes of North America, University of Califor- 
nia, Rv. Berkeley and Los Angeles pp. vii + 
353 and 127 pi. 



First Report of Aedes thibaulti Dyar and Knab 
in Connecticut and New York 

Robert C. Wallis and Loring Whitman 

The Department of Epidemiology and Public 

Health, Yale University School of Medicine, 

60 College Street, New Haven, 

Connecticut 06510 

The recorded distribution of Aedes thibaulti 
in the United States is in the southeastern 
region. According to Carpenter and La Casse 
(1955) this mosquito is found north to Ohio 
and west to Texas. Carpenter and La Casse also 
list it present in Alabama, Arkansas, Florida, 
Georgia, Illinois, Kentucky, Louisiana, Mississippi, 
Missouri, North and South Carolina and Tennes- 
see. Up to the present time there has _ been no 
publication of collection records of this species 
in New England, and the purpose of this note is 
to report the first collection of A. thibaulti in 
Connecticut and also in New York. 



A One-Piece Aluminum Cage Designed for 
Adult Mosquitoes 

K. E. Savage and R. E. Lowe 

Entomology Research Division, Agr. Res. Serv., 

U.S.D.A., Gainesville, Fla. 32601 

The literature contains numerous references to 
methods and techniques for collecting, trapping, 
and rearing mosquitoes. However, little informa- 
tion is available concerning standardized holding 
cages for mosquitoes. Apparently, there are as 
many different sizes and types of cages as there 
are researchers. 

The laboratory cages in use today undoubtedly 
evolved from wooden frames covered with screen 
wire. The adaptations included the use of glass, 
plastic, or doth sides, an entry sleeve s and some-